Emulsification of alkenyl succinic anhydride with an amine-containing homopolymer or copolymer

ABSTRACT

The present disclosure provides for a method of preparing and using an emulsion for treating a papermaking process. The emulsion is an oil-in-water emulsion of alkenyl succinic anhydride emulsified with a polymer comprising at least one primary or secondary amine containing monomer. The method comprises adding an oil-in-water emulsion to the papermaking process; wherein the oil-in-water emulsion comprises alkenyl succinic anhydride emulsified with a polymer comprising at least one primary or secondary amine containing monomer; and wherein the oil-in-water emulsion is added in an amount sufficient to improve sizing of the paper produced by the papermaking process. The primary or secondary amine may be a secondary amine comprising diallylamine, and the polymer may be a diallylamine-acrylamide copolymer.

This application is a continuation-in-part application of U.S. patentapplication Ser. No. 12/938,017, filed Nov. 2, 2010, the disclosure ofwhich is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

This disclosure relates generally to a novel composition and method forimproving paper and paperboard production. More specifically, thedisclosure relates to a composition and method for using alkenylsuccinic anhydride in combination with a diallylamine-containing polymeras a sizing emulsion in the papermaking process. The disclosure hasparticular relevance to the application of such compounds in sizingemulsion compositions as replacements for traditional polymers.

BACKGROUND

A resistance to hydrophilic liquid penetration (normally water), knownas “sizing,” is an important property of paper, both in the papermakingprocess and in the final product. For example, the extent to which apaper is weakened by the rewetting at the size press during productionis influenced by its degree of sizing. Additionally, a high level ofinternal sizing of a sheet contributes to the sheet's structuralstability in environments where the sheet may come in contact withliquid water. Beverage and food packaging are typical examples of theuse of board and paper products where a high level of sizing isdesirable.

Generally, resistance to water penetration is achieved by theintroduction of a sizing agent at the wet end of the papermakingprocess. A common sizing agent is alkenyl succinic anhydride (“ASA”).ASA-containing materials are used to impart a degree of hydrophobicityto paper fibers during production, and an overall resistance to liquidabsorption to the finished paper product. A drawback to using ASA as asizing material is that ASA is not water soluble and typically must beuniformly suspended in the pulp as an emulsion so that the ASA can makeadequate contact with the cellulosic fibers and, thus, create thedesired effect on the final product. A conventional sizing program isdisclosed in U.S. Pat. No. 4,657,946 to Rende et al., the disclosure ofwhich is hereby incorporated by reference in its entirety.

SUMMARY OF THE INVENTION

The present disclosure provides for a method of treating a papermakingprocess. The method comprises adding an oil-in-water emulsion to thepapermaking process. The oil-in-water emulsion comprises alkenylsuccinic anhydride emulsified with a polymer comprising at least oneprimary or secondary amine containing monomer. The oil-in-water emulsionis added in an amount sufficient to improve sizing of the paper producedby the papermaking process.

The present disclosure alternatively provides for an oil-in-wateremulsion comprising alkenyl succinic anhydride emulsified with a polymercomprising at least one primary or secondary amine containing monomer.

As it pertains to both the method and the composition, the oil-in-wateremulsion may comprise from 0.01 weight percent to 40 weight percentalkenyl succinic anhydride. The oil-in-water emulsion may comprise from0.001 weight percent to 20 weight percent polymer.

DETAILED DESCRIPTION OF THE INVENTION

While the embodiments described herein may take various forms, therewill hereinafter be described presently preferred embodiments with theunderstanding that the present disclosure is to be considered merely anexemplification and is not intended to limit the disclosure to thespecific embodiments illustrated.

It should be further understood that the title of this section of thisspecification, namely, “Detailed Description of the Invention,” relatesto a requirement of the United States Patent Office, and does not imply,nor should be inferred to limit the subject matter disclosed herein.

The present disclosure provides for a method of treating a papermakingprocess. The method comprises adding an oil-in-water emulsion to thepapermaking process. The oil-in-water emulsion comprises alkenylsuccinic anhydride emulsified with a polymer comprising at least oneprimary or secondary amine containing monomer. The oil-in-water emulsionis added in an amount sufficient to improve sizing of the paper producedby the papermaking process.

The present disclosure alternatively provides for an oil-in-wateremulsion comprising alkenyl succinic anhydride emulsified with a polymercomprising at least one primary or secondary amine containing monomer.

As it pertains to both the method and the composition, the oil-in-wateremulsion may comprise from 0.01 weight percent to 40 weight percentalkenyl succinic anhydride. The oil-in-water emulsion may comprise from0.001 weight percent to 20 weight percent polymer. The followingdefinitions are intended to be clarifying and are not intended to belimiting.

As it pertains to this disclosure, “papermaking process” means a methodof making paper and paperboard products from pulp comprising forming anaqueous cellulosic papermaking furnish (optionally, with mineralfillers, such as calcium carbonates, clays, etc.), draining the furnishto form a sheet, and drying the sheet. It should be appreciated that anysuitable furnish may be used. Representative furnishes include, forexample, virgin pulp, recycled pulp, kraft pulp (bleached andunbleached), sulfite pulp, mechanical pulp, polymeric plastic fibers,the like, any combination of the foregoing pulps. The steps of formingthe papermaking furnish, draining and drying may be carried out in anymanner generally known to those skilled in the art. In addition to thesizing emulsions herein described, other papermaking additives may beutilized as adjuncts with the polymer treatment of this invention. Suchpapermaking additives include, for example, retention aids (e.g.,microparticles, flocculants, polymeric and inorganic coagulants, etc.),wet and dry strength additives (e.g., cationic starches, polyamidoamineepichlorohydrin-based polymers), the like, and combinations of theforegoing.

As it pertains to this disclosure, “paper” and “sheet” are usedinterchangeably to mean an intermediate or product of a papermakingprocess made from an aqueous cellulosic papermaking furnish (optionally,with mineral fillers, such as calcium carbonates, clays, etc.) that hasbeen formed into a layer. Depending on the context, paper or sheet couldmean an intermediate or a product of a papermaking process.

As it pertains to this disclosure, “polymer” means homopolymer,copolymer, or any organic chemical composition made up of bondedrepeating “mer” units unless the particular context makes clear that onespecies is intended.

Disclosed herein are polymers comprising primary and/or secondaryamines, which will serve as surprisingly effective emulsifiers foralkenyl succinic anhydride as compared to the conventional water solublequaternary amines. In certain embodiments, the polymers are watersoluble polymers. While not wishing to be bound by the following theory,it is believed that the primary and/or secondary amines are somehowreactive with ASA, allowing the emulsified ASA to perform as a“polymeric” size as opposed to a conventional “small molecule” size.

As previously discussed, the polymers that are useful in theoil-in-water emulsions disclosed herein comprise alkenyl succinicanhydride emulsified with a polymer comprising at least one primary orsecondary amine containing monomer (The phrase “amine-containingpolymer” is used interchangeably herein with the phrase “a polymercomprising at least one primary or secondary amine containing monomer”).In certain embodiments, such amine-containing polymers have a molecularweight greater than 10,000 Daltons, but preferably below 2,000,000Daltons, where at least 1 mole percent and up to 99 mole percent of themer content of the polymer is a polymerizable primary and/or secondaryamine-containing monomer. In certain embodiments, the amine-containingpolymer have molecular weights from 200,000 to 1,500,000 Daltons. Incertain embodiments, at least ten mole percent and up to 60 mole percentof the mer units are amine containing vinyl- or allyl-monomers. Incertain embodiments, the amine-containing monomer in the polymer isdiallylamine.

In certain embodiments, the amine-containing polymer include a polymerwith randomly distributed repeating monomer units derived from at leastone of the following structures: Formulae I, II and/or their salt form'sthereof, and/or Formula III and/or its hydrolyzed form afterpolymerization, denoted as Formula IIIA, where x=z=0, if the formamideis 100% hydrolized:

wherein R can be hydrogen or alkyl; R₁, R₂, R₃, R₄, R₅, R₆ are,independently selected from hydrogen, alkyl, or alkoxylalkyl. FormulaeI, II, III, and IIIA independently may each be 0 mole percent. However,in certain embodiments where at least one of Formula I, II, III, and/orIIIA is utilized, the sum of Formulae I, II, III, and/or IIIA is fromone mole percent up to 99 mole percent, based upon the amine-containingpolymer or copolymer.

As previously discussed, in certain embodiments, the amine-containingpolymer is a copolymer. Various co-monomer(s) may be useful, including,but not limited to, one or more vinyl addition monomers includingnon-ionic, cationic, anionic, and zwitterionic, with non-ionic andcationic being the preferred co-monomers. The co-monomer(s) ispreferably water-soluble or at least results in a water-solublecopolymer.

Representative non-ionic co-monomers include acrylamide, methacrylamide,N,N-dimethylacrylamide, N,N-diethylacrylamide, N-isopropylacrylamide,N-vinylfoimamide, N-vinylmethylacetamide, N-vinyl pyrrolidone,hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropylacrylate, hydroxypropyl methacrylate, N-t-butylacrylamide,N-methylolacrylamide, vinyl acetate, vinyl alcohol, similar monomers,and combinations thereof. In certain embodiments, the co-monomer isacrylamide.

Representative anionic co-monomers include acrylic acid and its salts,including, but not limited to sodium acrylate and ammonium acrylate;methacrylic acid and its salts, including, but not limited to sodiummethacrylate and ammonium methacrylate;2-acrylamido-2-methylpropanesulfonic acid (“AMPS”); the sodium salt ofAMPS; sodium vinyl sulfonate; styrene sulfonate; maleic acid and itssalts, including, but not limited to the sodium salt, the ammonium salt,sulfonate, itaconate, sulfopropyl acrylate or methacrylate or otherwater-soluble forms of these or other polymerizable carboxylic orsulfonic acids; sulfomethylated acrylamide; allyl sulfonate; sodiumvinyl sulfonate; itaconic acid; acrylamidomethylbutanoic acid; fumaricacid; vinylphosphonic acid; vinylsulfonic acid; allylphosphonic acid;sulfomethylated acrylamide; phosphonomethylated acrylamide; itaconicanhydride; similar monomers, and combinations thereof.

Representative cationic co-monomers or mer units of the primary orsecondary amine include dialkylaminoalkyl acrylates and methacrylatesand their quaternary or acid salts, including, but not limited to,dimethylaminoethyl acrylate methyl chloride quaternary salt(“DMAEA•MCQ”), dimethylaminoethyl acrylate methyl sulfate quaternarysalt, dimethyaminoethyl acrylate benzyl chloride quaternary salt,dimethylaminoethyl acrylate sulfuric acid salt, dimethylaminoethylacrylate hydrochloric acid salt, dimethylaminoethyl methacrylate methylchloride quaternary salt, dimethylaminoethyl methacrylate methyl sulfatequaternary salt, dimethylaminoethyl methacrylate benzyl chloridequaternary salt, dimethylaminoethyl methacrylate sulfuric acid salt,dimethylaminoethyl methacrylate hydrochloric acid salt,dialkylaminoalkylacrylamides or methacrylamides and their quaternary oracid salts such as acrylamidopropyltrimethylammonium chloride,dimethylaminopropyl acrylamide methyl sulfate quaternary salt,dimethylaminopropyl acrylamide sulfuric acid salt, dimethylaminopropylacrylamide hydrochloric acid salt, methacrylamidopropyltrimethylammoniumchloride, dimethylaminopropyl methacrylamide methyl sulfate quaternarysalt, dimethylaminopropyl methacrylamide sulfuric acid salt,dimethylaminopropyl methacrylamide hydrochloric acid salt,diethylaminoethylacrylate, diethylaminoethylmethacrylate,diallyldiethylammonium chloride and diallyldimethyl ammonium chloride(“DADMAC”), similar monomers, and combinations thereof. When present,alkyl groups are generally C₁ to C₄ alkyl.

Representative zwitterionic co-monomers includeN,N-dimethyl-N-acryloyloxyethyl-N-(3-sulfopropyl)-ammonium betaine;N,N-dimethyl-N-acrylamidopropyl-N-(2-carboxymethyl)-ammonium betaine;N,N-dimethyl-N-acrylamidopropyl-N-(3-sulfopropyl)-ammonium betaine;N,N-dimethyl-N-acrylamidopropyl-N-(2-carboxymethyl)-ammonium betaine;2-(methylthio)ethyl methacryloyl-S-(sulfopropyl)-sulfonium betaine;2-[(2-acryloylethyl)dimethylammonio]ethyl 2-methyl phosphate;2-(acryloyloxyethyl)-2′-(trimethylammonium)ethyl phosphate;[(2-acryloylethyl)dimethylammonio]methyl phosphonic acid;2-methacryloyloxyethyl phosphorylcholine (“MPC”);2-[(3-acrylamidopropyl)dimethylammonio]ethyl 2′-isopropyl phosphate(“AAPI”); 1-vinyl-3-(3-sulfopropyl)imidazolium hydroxide;(2-acryloxyethyl) carboxymethyl methylsulfonium chloride;1-(3-sulfopropyl)-2-vinylpyridinium betaine;N-(4-sulfobutyl)-N-methyl-N, N-diallylamine ammonium betaine (“MDABS”);N,N-diallyl-N-methyl-N-(2-sulfoethyl) ammonium betaine; similarmonomers, and combinations thereof.

Generally, the amine-containing polymers used in this disclosure maytake the form of water-in-oil emulsions, dry powders, dispersions, oraqueous solutions. In certain embodiments, the amine-containing polymersmay be prepared via free radical polymerization techniques in waterusing free radical initiation.

ASA is commonly produced by the high temperature reaction of maleicanhydride (“MA”) and a long chain internal olefin where the olefin to MAratio is usually greater than 1. The type of olefin used to produce theASA can have a significant impact on product performance. The olefinsemployed in commercial ASA sizes typically contain a carbon chain lengthof 16-18. However, it should be understood that ASA useful in theoil-in-water emulsions described herein may be prepared from olefins ofdifferent carbon chain lengths.

ASA compounds prepared from MA and various internal olefins aredisclosed in U.S. Pat. No. 3,821,069. ASA compounds prepared from MA andmixtures of olefins, including internal olefins, are also disclosed inU.S. Pat. No. 6,348,132. The preparation of internal olefins by ametathesis reaction and a utility of the metathesized olefins in thepreparation of ASA compounds are disclosed in U.S. Patent ApplicationPublication No. 2003/0224945. The disclosures of each of thesereferences is herein incorporated by reference.

Stabilized size emulsions such as the oil-in-water emulsions of thepresent disclosure can be generally prepared using the procedures taughtin colloid science (e.g., S. E. Friberg & S. Jones, “Emulsions,” in theEncyclopedia of Chemical Technology, Vol. 9 (4th ed.), the disclosure ofwhich is herein incorporated by reference). The general concept consistsof imparting energy to a mixture of hydrophobic material (size in thiscase) and water in the presence of a stabilizer, which results in“small” droplets or particles of the hydrophobic material suspended inthe aqueous phase, thereby producing an oil-in-water emulsion. Themixing can be accomplished in any number of ways with the method ofmixing being immaterial to the application as long as the desiredresults are achieved.

Desired results normally refer to the average particle size and particlesize distribution. Mechanical means for emulsification, for example, caninclude high-speed agitators, mechanical homogenizers, or turbine pumps.The latter is frequently employed to prepare stabilized size emulsions.The equipment must be capable of preparing an emulsion particle size inthe range generally between about 0.01 and about 10 microns. A preferredparticle size is between about 0.5 to 3 microns. The emulsion size hererefers to the median diameter of a volume percent distribution obtainedwith a Malvern Mastersizer laser diffraction instrument, available fromMalvern Instruments, Ltd., Malvern, U.K. The median is defined as thediameter where 50% of the particles are greater than this value, and 50%are less than the value. The size of the emulsion can be controlled bythe amount of energy and stabilizer added. Normally, the emulsion wouldbe prepared from a mixture of the size, the polymeric stabilizer, andenough water to achieve desired dilution. As noted in, for example, U.S.Pat. Nos. 4,657,946 and 7,455,751, the disclosures of which are hereinincorporated by reference, a surfactant of the sorts identified thereincan be added to enhance the emulsification.

The oil-in-water emulsions or the ASA of the present disclosure may beused as an internal size or a surface size. Surface sizes are applied asa liquid solution or dispersion to the dry sheet, usually in a sizepress or at the calender stack. For example, in a simple puddle-typesize press, the paper sheet runs through a pond or puddle of sizingsolution and into a nip formed between two press rolls. Alternatively,the size solution may be sprayed into the nip on each side of the sheetand the nip forces the sizing solution into the sheet.

Internal sizes are typically added to the papermaking furnish in the wetend of the paper machine, prior to the headbox and the start of thedewatering process. The sizes are retained in the sheet of paper throughthe use of their emulsification polymers and/or typical retention anddrainage additives like coagulants, flocculants, and/or microparticles.In an effort to minimize deposition problems commonly associated withASA, the internal sizes are usually added as close as possible to theforming section.

Internal sizes may also be sprayed on the surface of the sheet afterformation of the wet web, for example, using a spray boom withappropriately placed nozzles across the width of the papermachine. Thespray nozzles should be designed and spaced to ensure even distributionof the compound on the sheet without disruption of the fibrous mat. Theplacement of the spray boom on the machine may be anywhere along thelength of the forming zone where gravity and vacuum dewatering occurs orimmediately prior to the press section or the dryer section. A commonlyused location for spraying chemical additives onto a paper sheet isbetween the wet line and the couch roll of a Fourdrinier-typepapermachine. The wet line is the location where the appearance of thewet web changes from a glossy, reflective surface to that of a dry,matte surface.

In certain embodiments, the oil-in-water emulsion of this disclosure mayoptionally be used in combination with one or more materials that arecationic in nature or capable of ionizing or dissociating in such amanner as to produce one or more cations or other positively chargedmoieties. Such cationic agents have been found useful as a means foraiding in the retention of sizing compositions in paper, and those ofskill in the art commonly refer to these as retention agents, aids,packages, and the like. Among the materials that may be employed ascationic agents in the sizing process are, for example, alum, aluminumchloride, polyaluminum chloride, long chain fatty amines, sodiumaluminate, substituted polyacrylamide, chromic sulfate, animal glue,cationic thermosetting resins, and polyamide polymers. Particularlysuitable cationic agents include, for example, cationic starchderivatives, including primary, secondary, tertiary, or quaternary aminestarch derivatives and other cationic nitrogen substituted starchderivatives. Such derivatives may be prepared from all types of starchesincluding corn, tapioca, potato, waxy maize, wheat, and rice. Moreover,they may be in their original granule form or they may be converted topre-gelatinized, cold water soluble products and/or employed in liquidform.

The cationic agents may be added to the stock, i.e., the pulp slurry,either prior to, along with, or after the addition of the oil-in-wateremulsion. To achieve maximum distribution, it may be preferable to addthe cationic agent subsequent to or in combination with the oil-in-wateremulsion. The addition to the stock of the oil-in-water emulsion and/orcationic agent may take place at any point in the papermaking processprior to the ultimate conversion of the wet pulp into a dry web orsheet. Thus, for example, the present sizing compositions may be addedto the pulp while the latter is in the headbox, beater, hydropulper,and/or stock chest.

To obtain advantageous sizing, it is generally desirable to uniformlydisperse the sizing agents throughout the fiber slurry in as small aparticle size as possible, in certain embodiments smaller than 2 micron.This may be achieved, for example, by emulsifying the sizingcompositions prior to addition to the stock. Emulsification is typicallyperformed using mechanical means such as, for example, high speedagitators, mechanical homogenizers, and/or through the addition of asuitable emulsifying agent.

The inventors have discovered that the employment of an oil-in-wateremulsion comprising ASA emulsified with an amine-containing polymer(particularly diallylamine (“DAA”)) in the papermaking processsurprisingly provides outstanding improvements in sizing performancewithout significantly affecting particle size distribution parameters.In certain embodiments, the amine-containing polymer is adiallylamine-acrylamide (“DAA-AcAm”) copolymer.

The oil-in-water emulsions are useful for the sizing of paper preparedfrom all types of both cellulosic and combinations of cellulosic withnon-cellulosic fibers. The cellulosic fibers that may be used include,for example, sulfate (a.k.a. Kraft), sulfite, soda, neutral sulfitesemi-chemical (“NSSC”), thermomechanical (“TMP”), chemi-thermomechanical(“CTMP”), groundwood (“GWD”), and any combination of these fibers. Anyof the foregoing cellulosic fibers may be bleached or unbleached. Thesedesignations refer to wood pulp fibers that have been prepared by any ofa variety of processes that are typically used in the pulp and paperindustry. In addition, synthetic fibers of the viscose rayon orregenerated cellulose type may be used.

Various types of pigments and fillers may be added to the paper that isto be treated using the methods and compositions of this disclosure.Such materials include, for example, clay, talc, titanium dioxide,calcium carbonate, calcium sulfate, and diatomaceous earths. Otheradditives, including, for example, alum, as well as other sizing agentsmay also be included in the present methods and compositions.

The amount of the oil-in-water emulsion that may be dosed into thepapermaking process may vary depending on, for example, the particularsizing composition employed, the particular pulp involved, the specificoperating conditions, the contemplated end-use of the paper, and thelike. Typical concentrations of the sizing composition, based on the dryweight of the pulp in the finished sheet or web, may range from 0.01pounds to 100 pounds of the oil-in-water emulsion per ton dry fiber(lb/ton) (5 grams to 50 kilograms per metric ton dry fiber), with a morepreferred range of 0.25 to 20 pounds per ton dry fiber (125 grams to 10kilograms per metric ton dry fiber). In certain embodiments, the sizingemulsion may be employed at a dose of from 0.5 to 5 lb/ton dry fiber(250 grams to 2.5 kilograms per metric ton dry fiber), with 1 to 4lb/ton dry fiber (500 grams to 2 kilograms per metric ton dry fiber)being a preferred dose range.

As previously discussed, in certain embodiments, the oil-in-wateremulsion is emulsified with a DAA-containing polymer as an emulsifyingagent. The polymer may be a DAA homopolymer, a copolymer of DAA, or anypolymer that at least partially comprises DAA. The concentration of thepolymer may vary depending on, for example, the particular sizingcomposition employed, the particular pulp involved, the specificoperating conditions, the contemplated end-use of the paper, and thelike. Typical concentrations range from 1 to 5 parts by weight polymerper 10 parts by weight ASA, including 1 to 4 parts by weight polymer per10 parts by weight ASA.

The mole percentage of DAA in the amine-containing polymer is also animportant variable when treating paper according to this disclosure. Incertain embodiments, the amine-containing polymer is a diallylaminehomopolymer. In other embodiments, the amine-containing polymer is aDAA/AcAm copolymer. In yet other embodiments, the amine-containingpolymer is a mixture of DAA homopolymer and DAA/AcAm copolymer. Anamine-containing polymer consisting of or consisting essentially of DAA(a DAA homopolymer or essentially a DAA homopolymer) can be expected toperform at least as well as the DAA/AcAm copolymer, as the sizingperformance of the emulsion has been noticeably improved for DAA/AcAmcopolymers when a greater DAA mole percentage is employed.

In those embodiments, where a DAA/AcAm copolymer embodiment is employed,the mole percentage of DAA in the DAA/AcAm copolymer can be within arange of 1 to 99 percent. The DAA/AcAm copolymer may be primarily madeup of DAA, i.e., may comprise more DAA monomer units than AcAm monomerunits. In those embodiments, where cost is a deciding factor in terms ofcomposition of the oil-in-water emulsion, a more preferable molepercentage of DAA in the amine-containing polymer may be 10 to 60, andincluding 10 to 40.

In certain embodiments, the oil-in-water emulsion comprises 0.01-40percent by weight ASA. In other embodiments, the oil-in-water emulsioncomprises 1-20 percent by weight ASA.

In certain embodiments, the oil-in-water emulsion comprises 0.001-20percent by weight amine-containing polymer. In other embodiments, theoil-in-water emulsion comprises 0.1-10 percent by weightamine-containing polymer. In certain embodiments, the amine-containingpolymer is DAA/AcAm copolymer which is present in an amount of 0.001-20percent by weight.

In certain embodiments, the oil-in-water emulsion comprises 8-12 percentby weight ASA. In certain embodiments, the oil-in-water emulsioncomprises 1-5 percent by weight polymer. In certain embodiments, theoil-in-water emulsion comprises 8-12 percent by weight ASA and 1-5percent by weight polymer. In certain embodiments, the weight percentageof polymer-to-ASA in the oil-in-water emulsion is 10-40%. In a preferredembodiment, the polymer-to-ASA weight percentage is 28-32%. For example,a 30% weight percentage of polymer-to-ASA would have 0.3 grams ofpolymer per 1 gram of ASA. In other words, a 30% weight percentage ofpolymer-to-ASA is the same as a polymer to ASA weight ratio of 0.3.

In certain embodiments, the oil-in-water emulsion is added to thepapermaking process at a point selected from the group consisting of:wet end; prior to a headbox; at the headbox; directly to the paper; atthe size press; and any combination thereof.

In certain embodiments, a mixing chamber is used to introduce theoil-in-water emulsion into the papermaking process. Examples of suchmixing chambers are disclosed in U.S. Pat. Nos. 7,550,060; 7,785,442;7,938,934; and 7,981,251, the disclosures of each of which are hereinincorporated by reference (e.g., PARETO Mixing Technology, availablefrom Nalco Company, 1601 West Diehl Road, Naperville, Ill. 60563), andthe Ultra Turax, model no. UTI-25 (available from MAO Works, Inc.,Wilmington, N.C.). It is envisioned that any suitable reactor or mixingdevice/chamber may be utilized in the methods disclosed herein tointroduce the oil-in-water emulsion.

The foregoing may be better understood by reference to the followingexamples, which are intended for illustrative purposes and are notintended to limit the scope of the invention.

EXAMPLES

The effects of emulsifying ASA with DAA/AcAm copolymer were investigatedin a laboratory handsheet study using a corrugated cardboard furnish.The study focused on answering the following questions:

1. Does the ASA emulsification with the DAA/AcAm copolymer result indistinct particle size distributions relative to a typical emulsifyingagent?

2. Does sizing response increase with the ASA emulsification with theDAA/AcAm copolymer relative to a typical emulsifying agent?

3. Does the DAA/AcAm:ASA ratio affect the sizing response?

Emulsions having 10% ASA by weight were prepared in a laboratoryminiblender. Water, emulsifier, and ASA were sequentially added andmixed for 120 seconds. Samples were extracted at 120 seconds (90 secondsfor the control samples) and particle size distribution measurementswere obtained using light scattering techniques. The emulsionscomprising the DAA/AcAm copolymer obtained after 120 seconds of mixingwere further diluted and used for the handsheets. The control samples(i.e., Examples 1-3) employed an acrylamide/dimethylaminoethylmethacrylate methyl chloride quaternary copolymer as their emulsifier.The examples according to the present disclosure (i.e., Examples 4-15)used a DAA/AcAm copolymer as their emulsifier. Two DAA/AcAm copolymers,having different DAA mole percents, were tested and are denoted in Table1 as DAA/AcAm-1 and DAA/AcAm-2. DAA/AcAm-1 contains 15 mole percent DAA,and DAA/AcAm-2 contains 35 mole percent DAA.

The target basis weight for the handsheets was 80 g/m². Three replicatesheets were prepared for each experimental condition. The 0.6% thinstock for each handsheet was mixed in a Dynamic Drainage Jar at 800 rpm.The desired amount of the ASA emulsion, a polyaluminum chlorideadditive, and a cationic flocculant were added in 15-second intervals.After mixing, the basesheet was formed in a handsheet mold using an80-mesh screen, pressed in a static press at 0.5 MPa for 5 minutes, anddried by passing the sheets through a drum dryer for one minute at about210° F.

The resistance to liquid penetration was determined using the HerculesSizing Test with a 25% formic acid, naphthol green dye solution at 80%reflectance. The conditions and results are recited in Table 1 below.

TABLE 1 Results of the experiments. Median % of Polymer ParticleParticle Hercules to Size after Volume >2 Sizing ASA Mixing μm afterTest Con- Polymer Weight for Mixing for ASA, Results, dition EmulsifierRatio 120 sec* 120 sec* lb/ton seconds  1 Control 0.14 1.04 18.23 3.0 60.9  2 Control 0.14 1.04 18.23 3.5  63.9  3 Control 0.14 1.04 18.234.0  70.0  4 DAA/AcAm-1 0.14 1.12 17.64 3.0  79.3  5 DAA/AcAm-1 0.141.12 17.64 3.5  79.6  6 DAA/AcAm-1 0.14 1.12 17.64 4.0  83.6  7DAA/AcAm-2 0.14 1.08 19.47 3.0  81.3  8 DAA/AcAm-2 0.14 1.08 19.47 3.5 88.9  9 DAA/AcAm-2 0.14 1.08 19.47 4.0 106.1 10 DAA/AcAm-1 0.30 1.007.63 3.0 153.1 11 DAA/AcAm-1 0.30 1.00 7.63 3.5 151.1 12 DAA/AcAm-1 0.301.00 7.63 4.0 134.1 13 DAA/AcAm-2 0.30 1.06 9.67 3.0 185.5 14 DAA/AcAm-20.30 1.06 9.67 3.5 197.9 15 DAA/AcAm-2 0.30 1.06 9.67 4.0 175.7 *Controlsamples were extracted after 90 seconds.

As can be seen from the data in Table 1, the use of an amine-containingpolymer results in improved resistance to liquid penetration, asevidenced by the higher results obtained from the Hercules Sizing testin Examples 4-15, as compared to the controls. Moreover, the use ofhigher amounts of amine-containing polymer:ASA provide further improvedresistance to liquid penetration, which is illustrated in Examples10-15.

All patents referred to herein, are hereby incorporated herein byreference, whether or not specifically done so within the text of thisdisclosure.

To the extent that the terms “include,” “includes,” or “including” areused in the specification or the claims, they are intended to beinclusive in a manner similar to the term “comprising” as that term isinterpreted when employed as a transitional word in a claim.Furthermore, to the extent that the term “or” is employed (e.g., A orB), it is intended to mean “A or B or both A and B.” When the applicantsintend to indicate “only A or B but not both,” then the term “only A orB but not both” will be employed. Thus, use of the term “or” herein isthe inclusive, and not the exclusive use. See Bryan A. Garner, ADictionary of Modern Legal Usage 624 (2d ed. 1995). Also, to the extentthat the terms “in” or “into” are used in the specification or theclaims, it is intended to additionally mean “on” or “onto.” Furthermore,to the extent that the term “connect” is used in the specification orthe claims, it is intended to mean not only “directly connected to,” butalso “indirectly connected to” such as connected through anothercomponent or components. In the present disclosure, the words “a” or“an” are to be taken to include both the singular and the plural.Conversely, any reference to plural items shall, where appropriate,include the singular.

All ranges and parameters disclosed herein are understood to encompassany and all sub-ranges assumed and subsumed therein, and every numberbetween the endpoints. For example, a stated range of “1 to 10” shouldbe considered to include any and all subranges between (and inclusiveof) the minimum value of 1 and the maximum value of 10; that is, allsubranges beginning with a minimum value of 1 or more (e.g., 1 to 6.1),and ending with a maximum value of 10 or less (e.g., 2.3 to 9.4, 3 to 8,4 to 7), and finally to each number 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10contained within the range.

While the present disclosure has been illustrated by the description ofembodiments thereof, and while the embodiments have been described inconsiderable detail, it is not the applicants' intent to restrict or inany way limit the scope of the appended claims to such detail.Additional advantages and modifications will readily appear to thoseskilled in the art. Therefore, the disclosure, in its broader aspects,is not limited to the specific details, the representative apparatus, orthe illustrative examples shown and described. Accordingly, departuresmay be made from such details without departing from the spirit or scopeof the applicants' general inventive concept.

We claim:
 1. A method of sizing paper produced by a papermaking process,the method comprising: adding an oil-in-water emulsion to thepapermaking process in an amount sufficient to size the paper; whereinthe oil-in-water emulsion comprises alkenyl succinic anhydrideemulsified with a copolymer consisting of diallylamine and at least oneof acrylamide and methacrylamide.
 2. The method of claim 1, wherein theoil-in-water emulsion comprises from 0.01 weight percent to 40 weightpercent of the alkenyl succinic anhydride.
 3. The method of claim 1,wherein the oil-in-water emulsion comprises 0.001 weight percent to 20weight percent of the copolymer.
 4. The method of claim 1, wherein theoil-in-water emulsion comprises 8-12 weight percent of the alkenylsuccinic anhydride and 1-5 weight percent of the copolymer.
 5. Themethod of claim 1, wherein the adding is performed at a point in thepapermaking process selected from the group consisting of: wet end;prior to a headbox; at the headbox; directly to the paper; at the sizepress; and any combination thereof.
 6. The method of claim 1, whereinthe adding is performed at a dosage rate of 0.01 lbs to 100 lbs of theoil-in-water emulsion per ton of dry fiber.
 7. The method of claim 1,wherein the copolymer has a mole percent of diallylamine ranging fromabout 1 to about 99 percent.
 8. The method of claim 1, wherein thecopolymer has a mole percent of diallylamine ranging from about 10 toabout 40 percent.
 9. The method of claim 1, wherein the oil-in-wateremulsion comprises from 0.01 weight percent to 40 weight percent alkenylsuccinic anhydride and from 0.001 weight percent to 20 weight percentcopolymer.
 10. An oil-in-water emulsion comprising alkenyl succinicanhydride emulsified with a copolymer consisting of diallylamine and atleast one of acrylamide and methacrylamide.
 11. The oil-in-wateremulsion of claim 10, wherein the oil-in-water emulsion comprises from0.01 weight percent to 40 weight percent of the alkenyl succinicanhydride.
 12. The oil-in-water emulsion of claim 10, wherein theoil-in-water emulsion comprises 0.001 weight percent to 20 weightpercent of the copolymer.
 13. The oil-in-water emulsion of claim 10,wherein the oil-in-water emulsion comprises 8-12 weight percent of thealkenyl succinic anhydride and 1-5 weight percent of the copolymer. 14.The oil-in-water emulsion of claim 10, wherein the copolymer has a molepercent of diallylamine ranging from 1 to 99 percent.
 15. Theoil-in-water emulsion of claim 10, wherein the copolymer has a molepercent of diallylamine ranging from of 10 to 40 percent.
 16. A methodof sizing paper during the papermaking process, the method comprising:adding an oil-in-water emulsion to the papermaking process in an amountsufficient to size the paper; wherein the oil-in-water emulsioncomprises alkenyl succinic anhydride emulsified with a copolymerconsisting of diallylamine and at least one of acrylamide andmethacrylamide.
 17. The method of claim 16, wherein the oil-in-wateremulsion comprises from 0.01 weight percent to 40 weight percent alkenylsuccinic anhydride and from 0.001 weight percent to 20 weight percentcopolymer.